Donatiello I

Donatiello I
Long-exposure photograph of Donatiello I[a]
Observation data (J2000 epoch)
Constellation	Andromeda
Right ascension	01h 11m 40.37s
Declination	+34° 36′ 3.2″
Distance	2.5−3.5 Mpc
Absolute magnitude (V)	−8.3±0.3
Characteristics
Type	Dwarf spheroidal
Apparent size (V)	0′.96 ± 0.30
Half-light radius (physical)	442±157 pc

Donatiello I, also known as Mirach's Goblin, is a dwarf spheroidal galaxy in the constellation Andromeda, located between 8.1 and 11.4 million light-years from Earth. It is a possible satellite galaxy of the dwarf lenticular galaxy NGC 404, "Mirach's Ghost", which is situated 60 arcminutes away. It is otherwise one of the most isolated dwarf spheroidal galaxies known, being separated from NGC 404 by around 211,000 light-years. The galaxy is named after its discoverer, amateur astronomer and astrophotographer Giuseppe Donatiello, who sighted the galaxy in a 2016 review of his archival long exposures from 2010 and 2013. Follow-up observations with the Roque de los Muchachos Observatory led to a scientific paper on its discovery being published in December 2018.

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